The card is Maroon. It looks pretty much like a Mileage Plus card.

The front says United Red Carpet Club at the top. The middle has your Mileage Plus number, your name, and the words "Member." The expiration date is also on the front as well.

There is a Star Alliance Logo on the front as well.

The back of the card contains a magnetic stripe and the usual "this card is property of United...blah blah blah"

There is also the phone number for Red Carpet Club customer service and the general United Reservations number.

(This is all from memory, my card is stuffed somewhere in my travel bag at the moment).